Setup a Raspberry Pi as a USB-over-IP server

19 Feb 2019 • Other Projects

I started working with Home Assistant using a Raspberry Pi 3 B+ and an HUSBZ-1 combo Z-Wave/ZigBee stick which worked well (if a little slow). However, I have concerns about long-term reliability of SD cards on the Pi and while performance was OK, I have a virtualization farm here that provides me much better performance and availability than an RPi could. The trouble is that I still needed access to the USB stick, and physically plugging it into one of my virtualization hosts would prevent me from moving the Home Assistant VM around in response to performance or availability situations in my farm.

More …

Sane management of multiple RTL-SDR dongles in Linux

15 Feb 2019 • Other Projects

I was looking to utilize a couple RTL dongles to monitor two ISM band frequencies commonly used in LoRa without buying an SDR with wide enough bandwidth to cover both ranges. I pretty quickly ran into issues with how SpyServer and rtl_tcp enumerate devices, which appears to be based mostly upon the order in which each device had been plugged in. With some work, I think I’ve come upon a flexible and secure solution to handle an arbitrary number of dongles on one system while maintaining deterministic control of each device. This means I can label an individual dongle, connect it to the desired antenna, and then connect to that dongle on the assigned TCP port every time, without regard to the order in which things have been plugged in.

More …

Reverse voltage protection and the moving serial number sticker

02 Feb 2019 • Nextion

I’ve been buying a fair number of the Nextion 2.4 LCDs over the past couple years and I noticed that a new PCB version started shipping sometime mid-to-late 2018. It looked like a typical mid-life product refresh, a couple diodes added on the serial lines, some pieces moved around the board, nothing too drastic. One thing that seem a bit odd was the relocation of the serial number sticker.

More …

Mapping out connector J2

30 Jan 2019 • Nextion

On each TJC/Nextion basic panel is a set of 5 pads labeled J2. Nextion has always been cagey about these pads and tend to delete any posts mentioning them (it’s something of a theme with them). Here’s what they look like:

More …